A dieta tem forte influência sobre a formação de carga ácida no metabolismo dos pacientes com doença renal crônica (DRC), portanto é um fator que pode influenciar na gravidade da acidose metabólica. Esta é uma condição comumente encontrada em estágios mais avançados da DRC. Proteínas vegetais, como a proteína texturizada de soja (PTS), poderiam proporcionar uma formação de carga ácida menor e, pelo seu conteúdo de isoflavonas, consideradas antioxidantes, contribuiriam para a melhora do estresse metabólico. O objetivo do estudo foi avaliar os efeitos da substituição de fontes proteicas de origem animal por fonte vegetal (soja), durante uma semana, em parâmetros sanguíneos e urinários de acidose em pacientes com DRC. Foram avaliados 28 pacientes com DRC estadios 3, 4 e 5 antes e após a substituição de fontes de proteínas animais de uma refeição principal (almoço ou jantar) por PTS ao longo de 7 dias. Antes e após a intervenção foram avaliados: ingestão alimentar por registros, a carga ácida potencial dos alimentos (CAPA), exames clínicos de rotinas, antropometria (peso, altura e IMC), composição corporal por bioimpedância de espectroscopia multifrequencial (BIS), parâmetros de acidez sanguínea e urinária (bicarbonato e pH urinário) e marcadores de estresse oxidativo (CAT e AOPP). Para análise de resultados foram utilizados testes não paramétricos de Mann-Whitney e também testes de correlação de Spearman que foram empregados para avaliação de associações entre as variáveis. O valor de p<0,05 foi considerado para a significância estatística. Encontramos que em9 uma semana de intervenção com PTS houve aumento significativo nos marcadores de BIC e pH sanguíneos, assim como no pH urinário. A maioria dos pacientes saíram do estado de acidose metabólica. O marcador de estresse oxidativo CAT mostrou melhora, porém o AOPP não apresentou aumento significativo. Em relação a composição corporal, houve diminuição do peso e aumento nos marcadores de hiperhiratação (HH), porém aumento na massa livre de gordura (MLG) e massa gorda (MG). Esses resultados mostram que a diminuição de CAPA na dieta, pela inclusão da PTS pode gerar uma melhora na acidose metabólica e no estresse oxidativo, consolidando que o manejo dietético através da inclusão de proteína vegetal pode ser uma abordagem nutricional importante no tratamento do paciente com DRC. / The diet has a strong influence on the formation of the acid load in the metabolism of patients with CKD, and this is a factor that can influence the severity of metabolic acidosis. It is a condition commonly found in more advanced stages of CKD. Vegetable proteins, such as textured soy protein (PTS), could provide a lower acid charge formation and, because of their content of isoflavones, considered antioxidants, would contribute to the improvement of metabolic stress. The objective of this study was to evaluate the effects of replacing animal protein source to plant source (soybean) for one week and analyze the blood and urine parameters of acidosis in patients with CKD. We evaluated 28 patients with CKD stages 3, 4 and 5 before and after replacing animal protein sources of the main meal, either lunch or dinner, with PTS over 7 days. Before and after the intervention it was evaluated: feed intake per records, Load Acid Potential Food (CAPA), clinical routines, anthropometry (weight, height and BMI), body composition by bioelectrical impedance multifrequency spectroscopy (BIS), blood and urine parameters (Bicarbonate and urinary pH) and oxidative stress markers (CAT and AOPP) Mann-Whitney non-parametric tests were used to analyze the results, as well as the Spearman\'s correlation tests to evaluate associations between the variables. The p value <0.05 was considered for statistical significance. We found that in one week of intervention with PTS there was a significant increase in BIC markers and blood pH, as well as urinary pH. Most of the patients were not in the state of metabolic acidosis. The CAT oxidative stress marker showed11 improvement, but AOPP showed no significant increase. Regarding body composition, there was a decrease in weight and an increase in the hyper hydration markers, but an increase in fat free mass and fat mass. These results show that the decrease of CAPA in the diet and the inclusion of the PTS can generate an improvement in metabolic acidosis and oxidative stress, consolidating the dietary management using plant protein inclusion and this can be an important nutritional approach in the treatment of patients with DRC.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-12-21T08:12:55Z No. of bitstreams: 2 Dissertação - Laura Garcia Vila - 2015.pdf: 2794084 bytes, checksum: ded55da11b6147f4147cce56cf18ec53 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-12-21T08:16:07Z (GMT) No. of bitstreams: 2 Dissertação - Laura Garcia Vila - 2015.pdf: 2794084 bytes, checksum: ded55da11b6147f4147cce56cf18ec53 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2015-12-21T08:16:07Z (GMT). No. of bitstreams: 2 Dissertação - Laura Garcia Vila - 2015.pdf: 2794084 bytes, checksum: ded55da11b6147f4147cce56cf18ec53 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-09-18 / Restraint induced stress in wild birds can be life threatening. Research for alternatives that minimize those risks iswell justified, sedation beinga suitable option. In the present study midazolam sedation was tested in two species of wild birds. Twenty-one blue-and-yellow macaws were randomly assigned in two groups, one receiving saline solution (control group) and the other approximately 7.5 mg/kg of midazolam (midazolam group) via an intranasal spray, in two different moments with a washout period of two months. Fourteen greater rheas were submitted to a similar protocol; however, the midazolam dosage was 1 mg/kg via an intramuscular route. After 10 min following sedative/saline application, physical exam (heart rate, respiratory rate and temperature) and venous blood collectionwere performed. Blood samples were processed for hemogasometry (only with macaws), hematology and biochemistry analyses. In macaws, midazolam application produced sedation; lower values for physical exam parameters and significantly (p<0.05) lower lactate, base excess and chloride concentrations, while pCO2, ctCO2 and HCO3 values were higher when compared with control group. In rheas, the only significant difference was the respiratory rate, being higher in the midazolam group. In macaws midazolam attenuated metabolic acidosis derived from restraint, showing a positive effect on stress reduction, proving an effective and safe alternative. In response to midazolam rheas showed inconstant reaction depending among individuals, with no reliable effect on stress restraint reduction. / O estresse produzido pela contenção em aves silvestres pode resultar em graves complicações. A procura por alternativas que minimizem tais riscos está plenamente justificada, sendo uma delas, a sedação. No presente estudo a sedação com midazolam foi testada em duas espécies de aves silvestres. Vinte e uma araras canindé foram randomizadas e divididas em dois grupos, um recebeu solução salina (grupo controle) e o outro aproximadamente 7,5 mg/kg de midazolam (grupo midazolam) via spray intranasal, em dois períodos de tempo diferentes, separados por dois meses. Catorze emas foram submetidas a um protocolo semelhante, porém a dose do midazolam foi 1 mg/kg,via intramuscular. Após 10 min do momento da aplicação do sedativo/salina foi feita a avaliação física (frequência cardíaca, frequência respiratória e temperatura) e a colheitado sangue por punção venosa. Foi realizada hemogasometria (somente nas araras), hematologia e bioquímica das amostras sanguíneas. Nas araras, a aplicação do midazolam produziu sedação, valores mais baixos para os parâmetros de avaliação física e concentrações significativamente (p<0.05) mais baixas de lactato, excesso de base e cloro enquanto que os valores de pCO2, ctCO2 e HCO3 foram mais elevados em comparação ao grupo controle. Nas emas, a única diferença significativa observada foi na frequência respiratória, sendo maior no grupo midazolam. Nas araras, o midazolam atenuou a acidose metabólica derivada da contenção, apresentando efeito na redução do estresse, mostrando-se uma alternativa segura e efetiva. A resposta ao midazolam nas emas variou em função do indivíduo,sem efeito consistente na redução do estresse.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-08-28T12:43:41Z No. of bitstreams: 2 Dissertação - Paulo Roberto Lucas Viana Filho - 2017.pdf: 2217340 bytes, checksum: e27042e1a0812b54894a35d43bcb4502 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-09-15T12:56:46Z (GMT) No. of bitstreams: 2 Dissertação - Paulo Roberto Lucas Viana Filho - 2017.pdf: 2217340 bytes, checksum: e27042e1a0812b54894a35d43bcb4502 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-09-15T12:56:46Z (GMT). No. of bitstreams: 2 Dissertação - Paulo Roberto Lucas Viana Filho - 2017.pdf: 2217340 bytes, checksum: e27042e1a0812b54894a35d43bcb4502 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-07-28 / The search for increasing the productivity and the quality, along the reduction the cost of production, is an unarguable need of the different systems for raising cattle. Besides that, the use of high-grain diet has become an indispensable tool for animal nutrition. On the other hand, such diet may cause an unbalance between the production and removal of volatile fatty acids in the rumen leading to a ruminal acidosis. Ruminal acidosis may result in lesions in the ruminal walls, contributing for the colonization and multiplication of bacteria, frequently leading to liver abscesses, rumenitis and claw lesions. This paper aims at describing the interrelation among liver abscesses, ruminal and claw lesions of bovine in a post mortem evaluation. The cattle was raised on pasture for 17 to 27 months. 90 days before slaughter, they were taken to feedlots. 1060 bovine were macroscopic evaluated while 98 were microscopically. Statistical analysis were performed using Pearson´s Qui-square. The macroscopic and microscopic analysis were classified in six scores, meaning one for animals without a lesion and five for the ones which had a lesion in their rumen. 328 lesions were found in 300 bovine (28.3%), that is, 88 (8.3%) had claw lesion, 10 (0.9%) showed liver abscesses and 230 (21.7%) presented rumenitis. None of the animals was simultaneously diagnosed with the three aforementioned lesions. 28 presented two different lesions: 26 (2.45%) had ruminal and claw lesions while 2 (0.19%) showed rumenal lesion and liver abscess. The microscopic evaluation of the rumen pointed out alterations in 21 (21.6%) slides. 16 animals presented discreet rumenitis, 2 had mild rumenitis and 2 showed chronic rumenitis. One animal had its rumen to be in a healing process. Out of the 98 rumen analyzed macroscopic and microscopically, 23 had macroscopic lesion while 10 presented the same alterations found microscopically: 7 diagnosed with hyperkeratosis, 2 with hyperemia and 1 ulcer case. The post mortem evaluation showed no interrelation of occurrence among rumenitis, liver abscess and claw lesion in Nelore bovine raised on a pasture up to 90 days before slaughter. The microscopic analyzes revealed ruminal lesions which were not identified in a macroscopic evaluation. It proved to be an extra resource for diagnosing the phase of rumenal lesions. / A busca pelo aumento da produtividade, qualidade e a redução dos custos de produção é uma necessidade indiscutível nos diferentes sistemas de criação de bovinos e o uso de dietas de alto grãos, ricas em carboidratos altamente fermentáveis e com baixos teores de fibra tornou-se uma ferramenta indispensável para a nutrição animal. Contudo essas dietas podem ocasionar um desequilíbrio entre a produção e remoção de ácidos graxos voláteis no rúmen, com consequente acidose rumenal. Este problema pode resultar em lesões na parede do rúmen, predispondo a colonização e multiplicação de bactérias, evoluindo com frequência para a formação de abscessos hepáticos, rumenite e enfermidades podais. O presente estudo objetivou inter-relacionar na avaliação post mortem, a ocorrência de rumenite, abscesso hepático e enfermidades podais em bovinos da raça Nelore, manejados a pasto durante a cria e recria e em sistema de confinamento durante a terminação, bem como realizar uma caracterização das principais lesões macroscópicas e microscópicas no rúmen. Foram avaliados macroscopicamente 1060 bovinos de corte pelo exame post mortem dos pés, fígado e rúmen e microscopicamente avaliou-se 98 rumens. Os dados foram analisados pelo teste de qui-quadrado, com nível de significância de 5%, para avaliar os pares de lesões. Para realizar a caracterização das lesões rumenais, as lesões macroscópicas e microscópicas foram classificadas em seis escores, sendo um para animais sem lesão e cinco para os animais com lesões. Foram encontradas 328 lesões em 300 (28,3%) bovinos, sendo 88 (8,3%) com enfermidades podais, dez (0,9%) com abscessos hepáticos e 230 (21,7%) com rumenite. Nenhum dos animais apresentou as três lesões simultaneamente. Dentre esses diagnósticos, 28 bovinos apresentaram duas destas enfermidades, sendo 26 (2,45%) com lesões tanto no rúmen quanto nos cascos e dois (0,19%) com lesão rumenal e abscesso hepático. O exame microscópico do rúmen verificou alterações em 21 (21,6%) lâminas. A rumenite aguda discreta foi a alteração predominante com 16 casos, seguida da rumenite aguda moderada e crônica, com dois casos cada uma. Encontrou-se apenas um caso de lesão em processo de cicatrização. Dentre os 98 rumens avaliados macro e microscopicamente, 23 apresentaram lesões macroscópicas e 10 tiveram as mesmas alterações verificadas na microscopia, sendo sete casos de hiperqueratose, dois casos de hiperemia e um caso de ulceração. Não houve inter-relação na avaliação post mortem, entre a ocorrência de rumenite, abscesso hepático e enfermidades podais em bovinos da raça Nelore, manejados a pasto durante a cria e recria e em sistema de confinamento na fase de terminação e a avaliação microscópica possibilitou a detecção de lesões rumenais que passaram despercebidas pela avaliação macroscópica, sendo um recurso diagnóstico extra para indicar o estágio de evolução das lesões rumenais.

Made available in DSpace on 2014-08-20T14:37:56Z (GMT). No. of bitstreams: 1 dissertacao_elizabeth_schwegler.pdf: 314372 bytes, checksum: 5a87d95b17fb4dee0132cf2f5b7f0824 (MD5) Previous issue date: 2009-03-17 / The aim of this study was to observe the efficiency of probiotics, monensin and selenium yeast fed to sheep induced to sub-acute ruminal acidosis (SARA) on the maintenance of normal ruminal and metabolic parameters. Thirty six sheep that averaged 12 months old and 31 ± 8 kg of body weight were used. The sheep were kept in a confinement system, receiving a diet based on tifton hay (Cynodon sp.) and concentrate. The sheep were divided in six groups, each one containing six animals. The treatments were: CO group, control, receiving the diet without any supplement; CS, with the addition of 1.5 g/animal/day of Sel-Plex® (selenium yeast); CM, with the addition of 11 ppm/kg of diet dry matter (DM) of monensin; CSM, with the addition of 11 ppm/kg of diet DM of monensin and 1.5 g/animal/day of Sel-Plex®; CY, with the addition of 3 g/animal/day of Yea-Sacc® (probiotic Saccharomyces cerevisiae); CSY, with the addition 3 g/animal/day of Yea-Sacc® and 1.5 g/animal/day of Sel-Plex®. The sheep receive this diet for 21 days before the start of the experiment. After the adaptation period the sheep were submitted to 2 days of fasting, receiving just the supplement and water ad libitum. After this, the sheep were submitted to 4 days of induced SARA, with concentrate ad libitum and received in the first morning meal the supplement specific for each group. Three days after the induction period, the sheep received the usual diet, but still receiving the supplements. Ruminal fluid collections were performed four times daily (8 and 12 AM and 4 and 7 PM) during the induction period and once daily (12 AM) in the recuperation period. The ruminal fluid was evaluated for pH, number of protozoa and chlorides concentration. Blood collection was performed once daily in the last day of adaptation, on the four days of induction and on the three days of recuperation. The metabolic parameters evaluated were: aspartate aminotransferase (AST), gamma glutamil transferase (GGT), lactate desidrogenase (LDH), glucose, calcium, chlorides, phosphorus, magnesium, sodium and potassium. The results showed that control group was superior regarding ruminal pH (P<0.05). Ruminal chlorides and number of protozoa did not differ between groups (P>0.05), only between day of the experiment (P<0.05). Also, there was no difference in the blood metabolic parameters between groups (P>0.05), but only between day of the experiment (P<0.05). Thus, the supplements used in this experiment were not efficient in maintaining ruminal and metabolic parameters at physiological levels in sheep submitted to sub-acute ruminal acidosis. / O objetivo do estudo foi determinar a eficácia do uso de probiótico (Saccharomyces cerevisiae), monensina e selênio levedura, sobre parâmetros ruminais e metabólicos de ovinos em situações de acidose ruminal sub-clínica (ARS). Foram utilizados 36 ovinos sem raça definida, com idade média de 12 meses e peso médio de 31 ± 8 kg. Os animais foram mantidos em sistema de confinamento, recebendo dieta a base de feno de tifton (Cynodon sp.) e concentrado. O experimento possuía 6 grupos experimentais, com 6 animais em cada grupo, tendo sido diferenciados pelo seu suplemento, sendo a dieta básica a mesma. Os tratamentos utilizados foram: grupo CO: controle, apenas a dieta básica; CS: com adição de 1,5 g /animal/ dia Sel-Plex® (selênio orgânico); CM: 11 ppm/ kg matéria seca da dieta de monensina sódica; CSM: 11ppm/kg matéria seca da dieta de monensina sódica, juntamente com 1,5 g/ animal/ dia de Sel-Plex®; CY: 3 g/ animal/ dia de Yea-Sacc® (probiótico a base de Saccharomyces cerevisiae); CSY: 3 g/ animal/ dia de Yea-Sacc® e ainda 1,5 g/ animal/ dia de Sel-Plex®. Os animais receberam esta dieta durante 21 dias, antes do início das coletas. Após o período de adaptação, os ovinos foram submetidos a 2 dias de restrição ao concentrado e volumoso, recebendo apenas o suplemento e água a vontade. Posteriormente os animais passaram por 4 dias de indução de ARS, com livre acesso à fração concentrada da dieta, recebendo no primeiro arraçoamento do dia os suplementos de cada tratamento. Nos três dias subseqüentes ao período de indução, os animais retornavam a dieta do período de adaptação recebendo os respectivos suplementos de acordo com cada tratamento (período de recuperação). Foram realizadas coletas de líquido ruminal 4 vezes ao dia (8, 12, 16 e 19 h), no período de indução, e às 12 h no período de recuperação. No líquido ruminal foi avaliado pH, contagem total de protozoários e teor de cloretos. A coleta de sangue foi realizada 1 vez ao dia no último dia de adaptação da dieta, nos quatro dias de indução e nos três dias de recuperação. Os parâmetros metabólicos avaliados foram: aspartato amino transferase (AST), gama glutaril transferase (GGT), desidrogenase láctica (LDH), glicose, cálcio, cloretos, fósforo, magnésio, sódio, potássio. Os resultados demonstram que o grupo controle se mostrou superior aos demais quanto ao pH do fluido ruminal (p<0,05). Os cloretos ruminais e a contagem total de protozoários não tiveram diferença entre grupos, apenas entre dias de indução. Nos parâmetros metabólicos, os resultados não tiveram diferença entre os tratamentos utilizados, apenas entre os dias de coleta. Conclui-se que os suplementos utilizados não foram eficazes em manter os parâmetros ruminais e metabólicos em níveis fisiológicos em animais submetidos à acidose ruminal sub-clínica.

La surveillance du bien-être fœtal pendant le travail repose essentiellement sur l’enregistrement du rythme cardiaque fœtal (RCF). Celui-ci, même continu pendant le travail, ne permet pas d’évaluer parfaitement l’oxygénation du fœtus ni le risque d’asphyxie néonatale. En effet, cet outil est imparfait et son évaluation subjective avec une importante variabilité d’interprétation inter et intra opérateur. Des examens dits de seconde ligne sont utilisés en pratique courante pour caractériser l’état fœtal : le prélèvement de sang fœtal au scalp pour l’étude de l’équilibre acido-basique du fœtus (pH ou lactates) ou la pose d’électrode au scalp pour étudier l’ECG fœtal (analyse du segment ST). Ces techniques sont néanmoins invasives et sont soumises à des contraintes techniques. Il y a donc un intérêt à développer des moyens d’évaluation du bien être fœtal à la fois objectifs et non invasifs afin de diminuer la survenue d’une asphyxie périnatale. En effet, celle-ci touche 3 à 8 nouveaux nés pour 1000 naissances. La mortalité en période post-natale est de 25 à 50% des cas et ceux qui survivent développeront des troubles sévères (épilepsie, retard neuro-cognitif et comportemental, paralysie cérébrale…). Au cours de l’accouchement, l’asphyxie périnatale se caractérise par une diminution du pH artériel ombilical. Cette mesure du pH sanguin est donc la mesure de référence pour déterminer la sévérité de l’asphyxie.Une des voies étudiées pour améliorer le dépistage des fœtus à risque d’acidose est l’analyse des modifications du système nerveux autonome (SNA) par analyse de la variabilité du rythme cardiaque fœtal. En effet, la fréquence cardiaque fœtale est en permanence sous l’influence du système nerveux autonome et sa variabilité (VFC) est un reflet de la balance sympathique / parasympathique. Le CHU de Lille a développé une nouvelle méthode d’analyse continue de la VFC ayant montré son efficacité chez l’adulte et chez le nouveau né pour l’évaluation du SNA. L’objectif de ce travail de Thèse est d’adapter cette technologie à l’analyse du SNA fœtal pour obtenir un nouvel indice appelé Fetal Stress Index (FSI) et d’évaluer sa pertinence en situation d’acidose.Cette preuve de concept a été effectuée de manière expérimentale chez le fœtus de brebis. Elle s’est réalisée en 2 temps. Nous avons tout d’abord évalué la performance du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes d’aptitude à détecter les variations du SNA. Après injection d’Atropine, parasympatholytique, ou de Propranolol, sympatholytique, nous avons montré que le FSI était une méthode efficace et spécifique d’évaluation des variations du tonus parasympathique du SNA. Cette étude a également montrée la supériorité du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes de sensibilité et de spécificité. Dans un second temps, nous avons évalué ce nouvel indice comme facteur prédictif de l’état acido basique du fœtus dans 2 modèles expérimentaux d’occlusion cordonale. Dans le premier modèle, l’acidose était obtenue par une occlusion continue du cordon avec une réduction de partielle du débit ombilical. Dans le second, nous réalisions des occlusions totales répétées à intervalles réguliers afin de mimer les contractions utérines lors du travail. Dans les 2 études, nous avons observé une hausse du FSI en cas d’acidose avec une corrélation significative entre le FSI et le pH, mais aussi entre le FSI et les lactates dans le second modèle.En conclusion, le FSI constitue un bon reflet de l’activité parasympathique fœtale. Cet indice permet d’étudier les variations du SNA fœtal avec une meilleure sensibilité et une meilleure spécificité que les méthodes usuelles d’analyse de la VFC et semble bien corrélé à l’état acido basique fœtal. Il s’agit donc d’un indice prometteur qu’il sera intéressant d’incorporer dans une analyse multi paramétrique du rythme cardiaque fœtal. / The monitoring of fetal well being during labor is essentially based on fetal heart rate (FHR) analysis. The recording of FHR, even continuously during labor, does not fully assess fetal oxygenation or neonatal risk of asphyxia. Indeed, this tool is imperfect and subjective with an important inter and intra-operator variability. Second-line examinations to characterize the fetal state are currently used in routine practice, i.e. scalp fetal blood sampling to study the fetal acid-base balance (pH or lactates) or scalp electrode placement to study the fetal ECG (ST segment analysis). These techniques are nevertheless invasive and subject to technical constraints. There is therefore an interest in developing both objective and non-invasive means of evaluating fetal wellbeing to reduce neonatal encephalopathy. Indeed, its prevalence is about 3 to 8 per 1000 births. Post natal mortality is about 25 to 50% and survivors will hav severe diseases (epilepsy, neurologic impairment, cerebral palsy…).One of the possibilities studied to better identify fetuses at risk for acidosis is the analysis of changes in the autonomic nervous system (ANS) in response to hypoxia.Indeed, the regulation of heart rate is dependent on the ANS and thus, its variability is a reflection of the sympathetic / parasympathetic balance. Analysis of heart rate variability (HRV) is a recognized non-invasive tool that is used to assess ANS regulation. The CHU Lille has developed a new continuous tool for the analysis of HRV, which demonstrated its efficacity in adults and neonates to evaluate the ANS. The objective of this thesis was to develop its index, called Fetal Stress Index (FSI), in the fetus and to evaluate it in conditions of acidosis.The study was experimental in a sheep model chronically instrumented and was in 2 steps. First, we evaluate the performance of our method compared to commonly used HRV analysis, regarding the ability to detect the variation of variations of the ANS. After injection of atropine, to inhibit parasympathetic tone, or propranolol to block sympathetic activity, we shown that our method appeared to be effective in detecting parasympathetic inhibition and, moreover, was superior to classical analysis of HRV in terms of sensibility and specificity.In a second time, we evaluated this new index as a predictive factor of the fetal acid-base state in 2 experimental models of fetal hypoxia by occlusion of the cord. In the first one, acidosis was obtained through a partial occlusion of the umbilical cord and in the second one, though repetitive complete occlusion as uterine contractions during labor. In those two studies, we observed a raise of our index in case of acidosis with a correlation beetween FSI and pH and also FSI and lactates in the second model.In conclusion, the FSI reflects fetal parasympathetic activity, has a better detection than others usual methods, and seems well correlated to fetal acid-base status. It is a promising index and it will be interesting to incorporate it in a multi parametric analysis of fetal heart rate to predict acidosis.

The caudal solitary complex (cSC) is a cardiorespiratory integrative center in the dorsal medulla oblongata that plays a vital role in the central CO2-chemoreceptive network. Neurons in this area respond to hypercapnic acidosis (HA) by a depolarization of the membrane potential and increase in firing rate, however a definitive mechanism for this response remains unknown. Likewise, CO2-chemoreceptive neurons in the cSC respond to hyperoxia in a similar fashion, but via a free radical mediated mechanism. It remains unknown if the response to increased pO2 is merely an increase in redox signaling, or if it’s the result of a pathological state of redox stress. Importantly, free radical production is known to be stimulated by increasing pO2, and can be exacerbated downstream by the addition of CO2 and its subsequent acidosis. Conditions of hyperoxia in combination with HA can therefore become detrimental in several scenarios, including O2 toxicity seizures in divers and stranded submariners, as well as in cases of ischemia-reperfusion injury and sleep apneas. As such, we sought to not only determine how O2 and CO2 interact to affect cellular excitability in the cSC, but also if these cells exhibited increases in redox signaling and/or stress. We employed sharp-electrode intracellular electrophysiology to study whole-cell electrical responses to varied combinations of hyperoxia (0.4 0.95/1.95 ATA O2) and HA (0.05 0.1 ATA CO2). Additionally, we used fluorescence microscopy under similar conditions to study changes in the production rates of various free radicals, including superoxide (˙O2-), nitric oxide (˙NO), and a downstream aggregate pool of CO2/H+-dependent reactive oxygen and nitrogen species (RONS). Finally, we used several colorimetric assays to measure markers of oxidative and nitrosative stress, including malondialdehyde, 3-nitrotyrosine, and protein carbonyls. Our hypothesis for these experiments was that hyperoxia and HA alone could produce effects, but would be more pronounced when used together. As such, we saw that ~89% of cells tested that were sensitive to both hyperoxia and HA showed larger firing rate responses to HA during an increased background O2 (0.9 and/or 1.9 ATA) after showing a smaller response or no response to HA during control levels O2 (0.4 ATA). Additionally, we noted that the rate of ˙O2- fluorescence increased in response to hyperoxia, but only during pharmacological inhibition of its reactions with ˙NO and SOD. Likewise, the rate of ˙NO fluorescence increased during hyperoxia compared to control O2, but only during pharmacological scavenging of ˙O2-. Downstream, our aggregate pool of RONS showed increased rates of fluorescence during both hyperoxia alone and HA in control O2, however the most prominent increases were seen during hypercapnic hyperoxia. Finally, no significant effects were seen when probing for markers of redox stress in response to hyperoxia and hypercapnic hyperoxia. Overall, these results suggest that the increased excitability seen in cSC neurons during hypercapnic hyperoxia is the result of physiological redox signaling rather than pathological redox stress. Further research needs to be done to determine how this redox mechanism is specifically resulting in increased cellular excitability.

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No description available.

The nucleotide excision repair (NER) pathway is essential for repair of UV-induced bulky DNA lesions. NER is divided into two subpathways: global genome repair (GGR) and transcription-coupled repair (TCR). UVC radiation has been shown to result in the formation of bulky DNA lesions, which are removed by NER. Previous published reports have shown a role for the p53 tumour suppressor protein in GGR and TCR, but the involvement of p53 in TCR has been controversial. In addition, it has also been suggested that hypoxia affects NER and expression of p53. In the present work, the role of p53, hypoxia and HIF-lα in NER was investigated. It was determined that p53 overexpression in primary human fibroblasts resulted in up-regulation of both the GGR and TCR subpathways of a UV -damaged reporter gene. Pre-treatment of cells with low UVC-fluence and p53 overexpression also induced an upregulation of GGR and TCR. These results are consistent with a p53-dependent upregulation of TCR and GGR of the UVC-damaged reporter gene, as well with a UV-inducible TCR and GGR that is dependent on p53 expression prior to UV treatment. Hypoxia coupled to low pH induced a transient up-regulation of p53 expression and NER in human primary normal fibroblasts and a concomitant decrease in UVC sensitivity. In contrast, in tumour cells hypoxia coupled to low pH resulted in a delayed, but not absent up-regulation of NER, which was p53-independent and did not result in a decrease in UVC sensitivity. We report here that it is the early transient p53-dependent up-regulation induced by hypoxia coupled to acidosis in human primary normal fibroblasts that may play a significant role in cellular UVC sensitivity. These data suggest a different cellular NER response to hypoxia compared to hypoxia coupled to low pH. The NER response to hypoxia and hypoxia coupled with acidosis was also different in primary cells when compared to tumour-derived cells. It was demonstrated that expression of dominant-negative HIF-lα in rat prostate tumour cells results in a reduction in host cell reactivation (HCR) of a UV-damaged reporter gene when compared to that in wild-type HIF-lα cells under normoxic conditions suggesting that basal HIF-lα expression may play an important role in NER. In addition we showed that hypoxia induced an up-regulation of NER in human primary normal fibroblasts that was delayed, but not absent in TCR-deficient CSB cells, suggesting a role for hypoxia in up-regulation of the GGR pathway of NER of a UVdamaged reporter gene. In contrast, HIF-lα-overexpression under conditions of hypoxia resulted in a down-regulation of NER in normal fibroblasts, which was delayed, but not absent in CSB fibroblasts. These results suggest that HIF-1α and CSB are involved in a hypoxia-induced NER response. This work provides further evidence that both GGR and TCR are p53-dependent. In addition, this study provides evidence that hypoxia and hypoxia coupled to acidosis can up-regulate NER in both primary and tumour cells, and that HIF-lα and the CSB protein play an important role in a hypoxia-induced NER response. / Thesis / Doctor of Philosophy (PhD)

No / The molecular identity of ion channels which confer PCO(2)/pH sensitivity in the brain is unclear. Heteromeric Kir4.1/Kir5.1 channels are highly sensitive to inhibition by intracellular pH and are widely expressed in several brainstem nuclei involved in cardiorespiratory control, including the locus coeruleus. This has therefore led to a proposed role for these channels in neuronal CO(2) chemosensitivity. To examine this, we generated mutant mice lacking the Kir5.1 (Kcnj16) gene. We show that although locus coeruleus neurons from Kcnj16((+/+)) mice rapidly respond to cytoplasmic alkalinization and acidification, those from Kcnj16((-/-)) mice display a dramatically reduced and delayed response. These results identify Kir5.1 as an important determinant of PCO(2)/pH sensitivity in locus coeruleus neurons and suggest that Kir5.1 may be involved in the response to hypercapnic acidosis.